Format string warnings: don't a.k.a. wchar_t with wchar_t.

This fixes the case where Clang would output:
 error: format specifies type 'wchar_t *' (aka 'wchar_t *')

ArgTypeResult::getRepresentativeTypeName needs to take into account
that wchar_t can be a built-in type (as opposed to in C, where it is a
typedef).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149387 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/FormatString.cpp b/lib/Analysis/FormatString.cpp
index a0633c8..30bfe4b 100644
--- a/lib/Analysis/FormatString.cpp
+++ b/lib/Analysis/FormatString.cpp
@@ -373,7 +373,7 @@
 
 std::string ArgTypeResult::getRepresentativeTypeName(ASTContext &C) const {
   std::string S = getRepresentativeType(C).getAsString();
-  if (Name)
+  if (Name && S != Name)
     return std::string("'") + Name + "' (aka '" + S + "')";
   return std::string("'") + S + "'";
 }